Apparatus for feeding powder



Sept. 22, 1964 J. c MA'NLEY APPARATUS FOR FEEDING POWDER Filed Sept. 13, 1962' 2 Sheets-Sheet 1 g 30 I-lm 34 I'll/111727 INVENTOR. fill/v 6f ANL 7 Sept. 22, 1964 J. c MANLEY 3,149,759

APPARATUS FOR FEEDING POWDER Filed Sept. 15, 1962 2 Sheets-Sheet 2 INVENTOR. JOHN 6. MA; EY

A TI'OR/VEY United States Pat 3,149,759 APPARATUS FOR FEEDING POWDER John C. Manley, Bradford, Pa, assignor to Corning Glass Works, (Zorning, NAG, a corporation of New York Filed Sept. 13, 1962, Ser. No. 223,350 6 Claims. (Cl. 222-493) This invention relates to powder feeders, and more particularly to powder feeders where the powder is fed in gas suspension, but is in no way limited to such applications.

Heretofore, it has been desirable to feed powder, for example, to plasma jet guns or the like, in continuous, uniform and comparatively small amounts. Prior art devices, employing worm feeds or the like have been found to lack the uniformity of feed desired and were unable to feed comparatively small amounts of powder such as, for example, 1 cubic centimeter per minute. Furthermore, many powders tend to cake and form large masses as a result of absorbing moisture, making uniform feeding difi'icult.

The object of the present invention is to provide a powder feeder for feeding powder in small uniform amounts.

Another object of the present invention is to provide an improved continuous powder feeder.

Still another object is to provide a powder feeder wherein the powder is maintained dry.

A further object is to provide a method for uniformly feeding powder in a gas suspension.

According to the present invention a system is provided whereby powder is conveyed along a desired path by vibratory or the like means. The path comprises a spiralled track or groove on the surface of a cylinder. As the powder is conveyed, means regulating the cross sectional size of the powder bath, remove the powder in excess of a predetermined desired amount. The cylinder is disposed within a pressure vessel into which vessel a dry gaseous medium is introduced. As said powder reaches the end of said track, it is deposited at the entrance to the only outlet for the gaseous medium. By regulating the volume of said gaseous medium, all of the powder so deposited is carried along by the gaseous medium to the point of utilization.

Additional objects, features, and advantages of the present invention will become apparent, to those skilled in the art, from the following detailed description and the attached drawings on which, by way of example, only the preferred embodiments of this invention are described.

FIG. 1 is a cross sectional elevation of an apparatus embodying the present invention.

FIG. 2 is a cross sectional plan view of the apparatus of FIG. 1 taken along 2-2 thereof.

FIG. 3 is a cross sectional elevation taken along 3-3 of FIG. 2.

FIG. 4 is a cross sectional elevation taken along 4-4- of FIG. 2.

FIG. 5 is a cross sectional plan view of another embodiment of the apparatus of this invention.

FIG. 6 is a cross sectional elevation taken along 66 of FIG. 5.

Referring to FIG. 1 of the drawings, the apparatus is arranged on a rigid supporting base 10, upon which a vibration mechanism is mounted. The vibration mechanism comprises mounting blocks 12, spring members 14, electro-magnet 16, and ferromagnetic armature block 18. Such a vibration mechanism and the operation thereof is well known in the art and is shown here as one example of vibration producing means. Other means known in the art may also be used.

snares Patented Sept. .22, 1964 Mounted upon the vibration mechanism is the powder feeder pressure vessel comprising base 20, top 22, and shell 24. Said vessel is maintained pressure tight by compression gasket 26 between shell 24 and base 20, and compression gasket 28 between shell 24 and top 22. Gaskets 26 and 28 are compressed by means of shaft 30, passing through the vessel, and nut 32. Compression gasket 34 is disposed between nut 32 and top 22.

Hollow cylinder 36, having a spiralled track or groove 38 formed on the outer surface thereof, is positioned substantially concentrically within shell 24. Track or groove 38 is bounded at the outer edge by rim 39. A gaseous medium from a suitable source, not shown, is fed to said pressure vessel by means of tubes 40 and 42, and passage 44. The gaseous medium outlet is through chamber 46, tube 48, passage 5d and tube 52 to the point of utilization.

The composition of the gaseous medium employed in this invention is not critical, as long as it is compatible with the powder being conveyed. To prevent powder caking due to moisture, said gaseous medium is preferably dry. Gases, such as nitrogen, air, argon, helium, hydrogen, oxygen and the like are examples of suitable gaseous mediums.

Powder 54 is loaded into the apparatus between cylinder 36 and shell 24 as well as within the cylinder 26, both of which spaces may comprise the powder reservoir. Holes 55 are formed through cylinder 36 to permit the powder within cylinder 36 to issue therefrom and be utilized. Upon energizing electro-magnet 16, powder 54 is caused to be conveyed along the path provided by spiralled groove 38 until the powder reaches chamber 46. The rate of powder feed is primarily controlled by the frequency and amplitude of vibration and the cross sectional size of groove 28. However, as shown in FIGS. 2 and 4, powder volume is also in part regulated by blade 58, which is rigidly mounted to cylinder 36, and is disposed in relation to groove 38 so that the desired volume of powder will be conveyed past it, while the excess will be caused to fall over the side of cylinder 36 and drop into the powder reservoir between shell 24 and cylinder 36. The measured volume of powder conveyed may be easily varied by the shape of blade 58.

Referring to FIGS. 2 and 3 it is seen that as the measured volume of powder reaches chamber 46, and drops therein, it is picked up and carried in suspension by the gaseous medium, since, the only outlet for the gaseous medium being introduced through tube 42 is through chamber 46 and thereafter through tubes 48 and 52. By regulating the volume of the gaseous medium introduced and flowed into the pressure vessel all of the powder dropping into chamber 46 will be picked up and carried to the point of utilization. The volume of the gaseous medium required will vary with the amount, size, and composition of the powder being fed, however, this can be readily determined by one skilled in the art.

FIGS. 5 and 6 illustrate another embodiment of this invention. An open channel 60 is disposed within the upper spiral of track or groove 38, partly extending over the open central portion of hollow cylinder 36 and terminating at the open end of tube 62. Channel 60 is held in place by clamps 54 and 66. The portion of channel 69 which extends over the central portion of cylinder 36 may be suitably shaped so that only the desired volume of powder is held by it while the excess falls over the side into the powder reservoir. As the desired volume of powder reaches the end of channel 60 and drops off at the entrance to tube 62, it is picked-up and carried in suspension through tube 62 by the gaseous medium, since the only outlet for the gaseous medium being introduced through tube 42, is tube 62. By regulating the volume of the gaseous medium introduced into the pressure {B vessel all of the powder dropping off at the end of channel 60 at the entrance of tube 62 will be carried along by the gaseous medium.

Substantially, any type of powder may be conveyed by the apparatus and method of this invention, including for example, powdered glass, powdered metals, polyethylene, epoxies, polyesters, and the like. The powder feeder of this invention is suitable to feed powders to plasma jet guns, process vessels, flame torches, and the like or may be used for package loading.

It has been found that with the powder feeder of this invention, rates of powder ranging down to approximately 1 cubic centimeter per minute or less may be fed continuously and uniformly. The upper range limit is determined solely by the physical size and capacity of the apparatus.

It is readily seen that although the spiralled groove was shown to be formed on the outer surface of the cylinder, it may obviously be formed on the inner surface thereof, for all embodiments. In such applications, the powder may be supplied to the center of the cylinder only, which would form the powder reservoir.

Although the present invention has been described with respect to specific details of certain embodiments thereof, it is not intended that such details be limitations upon the scope of the invention except insofar as set forth in the following claims.

What is claimed is:

l. A powder feeder comprising a pressure-tight vessel, a track within said vessel forming a path for conveying a powder thereon, vibratory means to cause said powder to be conveyed to one end of said track, an outlet for said powder located substantially at said one end of said track, an inlet opening through which a gaseous medium is introduced into said vessel, said outlet for said powder comprising also the outlet for said gaseous medium, whereby said powder is entrained in said gaseous medium and carried in suspension therewith through said outlet.

2. The powder feeder of claim 1 wherein said track is a spiralled groove formed on the outer surface of a hollow cylinder.

3. The powder feeder of claim 1 wherein said track is a spiralled groove formed on the inner surface of a hollow cylinder.

4. A powder feeder comprising a pressure-tight vessel, a track within said vessel forming a path for conveying a powder thereon, said track comprising a spiralled groove which has a rim at the outer edge thereof and is formed on the outer surface of a hollow cylinder, vibratory means to cause said powder to be moved toward one end of said track, said vibratory means regulating the rate of movement of said powder, an outlet for said powder located substantially at said one end of said track, means for introducing a dry gas into said vessel, said outlet for said powder comprising also the outlet for said gas, whereby said powder is entrained in said gas upon being exhausted therewith through said outlet.

5. A powder feeder comprising a pressure-tight vessel, a track within said vessel forming a path for conveying a powder thereon, said track including a vertically spiralled groove formed on the outer surface of a hollow cylinder and an open channel having its one end disposed within the upper spiral of said groove and its other end disposed over the open central portion of said cylinder, vibratory means to cause said powder to be conveyed along said track toward said other end of said open channel, said vibratory means regulating the rate of feed of said powder, means for introducing a gas into said vessel, and an outlet for said gas, said outlet being disposed immediately adjacent the said other end of said open channel, whereby powder reaching said other end will be entrained in said gas as it passes through said outlet.

6. A powder feeder comprising a pressure-tight vessel, a track within said vessel forming a path for conveying a powder thereon, said track including a vertically spiralled groove formed on the inner surface of a hollow nel, whereby powder reaching said other end will be entrained in said gas as it passes through said outlet.

References Cited in the file of this patent UNITED STATES PATENTS 2,779,510 Wilson et a1 Ian. 29, 1957 

1. A POWDER FEEDER COMPRISING A PRESSURE-TIGHT VESSEL, A TRACK WITHIN SAID VESSEL FORMING A PATH FOR CONVEYING A POWDER THEREON, VIBRATORY MEANS TO CAUSE SAID POWDER TO BE CONVEYED TO ONE END OF SAID TRACK, AN OUTLET FOR SAID POWDER LOCATED SUBSTANTIALLY AT SAID ONE END OF SAID TRACK, AN INLET OPENING THROUGH WHICH A GASEOUS MEDIUM IS INTRODUCED INTO SAID VESSEL, SAID OUTLET FOR SAID POWDER COMPRISING ALSO THE OUTLET FOR SAID GASEOUS MEDIUM, WHEREBY SAID POWDER IS ENTRAINED IN SAID GASEOUS MEDIUM AND CARRIED IN SUSPENSION THEREWITH THROUGH SAID OUTLET. 